An air-cooled two-cycle internal combustion engine, for example, is generally provided with an air cleaner and a muffler respectively on both sides of the cranksshaft of the engine and with a fuel tank below them.
Conventionally, in this kind of internal combustion engine, in order to reduce the size and weight of the engine body, the above mentioned air cleaner and muffler have been formed to be of necessary minimum sizes not projecting below the lower surface of the above mentioned engine body and the fuel tank formed to be of a merely substantially rectangular parallelepiped has been provided below and over all of the above mentioned air cleaner, engine body and muffler so that the fuel may be sufficiently carried.
As mentioned above, in the conventional internal combustion engine, as the air cleaner and the muffler have been limited at the lower ends thereof by the fuel tank, the capacities of the air cleaner and the muffler have not been able to help to be made small. Therefore, there have been defects that the suction and exhaust sounds have not been able to be well reduced and that the output has not been able to be improved.